The present invention relates generally to crop cutting implements and is particularly directed to an arrangement for improving cutting efficiency in a crop cutting implement and protecting the cutting mechanism from damage.
The cutting mechanism of a row-crop head, such as in a grain or soybeam combine, or in hay mowing equiment is generally based on a scissors action between a sickle bar and attached sickle sections which are displaced horizontally in a reciprocating manner through a horizontal slot in a sickle guard to sever the hay or grain stalk. The horizontal slot or gap confines and defines the path of travel of the reciprocating sickle sections and provides cutting action between the reciprocating sickle sections and the upper surface of the lower sickle guard member. In the past, a separate hold-down plate has been attached at various points along the width of the sickle bar to hold the sickle sections down against the upper surface cutting edges of the lower sickle guard member. In this type of sickle guard arangement, the wear and abrasion which occurs between the reciprocating sickle sections and the upper and lower guard members during usage results in an increase in the depth of the gap or horizontal slot between the upper and lower guard members. Thus, if these hold-down plates, or the upper guard members, are not kept properly adjusted, the sickle sections tend to ride up away from the upper surface cutting edge of the lower sickle guard member thereby permitting the hay or grain stalks to slide under the sickle sections. This action results in reduced cutting efficiency and clogging of hay or lower grain yield. In addition, the increased displacement between the reciprocating sickle sections and the sickle guard edges increases the likelihood of the reciprocating sickle sections catching the upper lip of the sickle guard and breaking it off. Similarly, this increased displacement also increases the possibility of a foreign object such as a stone becoming lodged between these cutting surfaces and damaging them.
In the past, attempts were made to avoid these problems by either reducing the speed of the cutting implement or by periodically checking the alignment of the complementary cutting surfaces and reconfiguring the individual sickle guards or the hold down plates such as by means of a hammer where necessary. More often, this cutting edge misalignment was merely ignored and the farmer realized reduced crop yields.
In the case of soybeans, the major cause of shattering loss, which accounts for approximately 28% of all harvesting losses, is the jolt caused by the impact of the sickle blade with the soybean stalk. Shattering causes the beans to be knocked out of the pods and onto the ground where they remain unharvested. With crop losses ranging up to 5-6 bushels per acre and a portion of these losses due to shattering, the need for an improved means for severing and gathering the crop in the field is readily apparent.
The present invention is intended to provide such an improved means for cutting crops and reducing crop losses. This is accomplished in the present invention by maintaining the cutting edges in a multi-section sickle assembly in proper spaced relation for insuring optimum cutting action while protecting the reciprocating sickle sections from damage.